Virtually all of the controls for operator controllable functions in present-day vehicles, ranging from automobiles and trucks to farm implements and aircraft, are located on their dashboards, seats, and/or doors. To operate such a control requires the operator to both move a hand from the steering wheel to the control and to divert his attention from the view ahead to locate the control to be operated. This diversion can be both unsafe and inconvenient.
Systems for overcoming these drawbacks by mounting controls on or near the vehicle steering wheel have been proposed. However, these systems fail to satisfy customer needs because they either (1) have too many switches or (2) control only a few functions. To illustrate the first extreme, a proposed prototype van, pictured in the Jan. 13, 1986 edition of the Detroit Free Press and the May 1986 issue of Car and Driver magazine, is equipped with a steering wheel having over 40 switches--certainly enough to distract and confuse the operator who is deciding which switch to activate. At the other extreme, the system disclosed by Kishi et al, in U.S. Pat. No. 4,456,903 has a small number of steering wheel-mounted switches for operating a speed control device. In contrast to these two extremes, it is highly desirable to control more functions with a small number of switches.
Operator-actuated controls are used only relatively infrequently and the functions to be served tend to cluster in natural groups of a few related functions, such as radio controls, climate controls, and so forth. It is therefore possible to use only a few switches to control many functions, group by group. This can be done by dedicating the switches to a single group of related functions at a time, and by associating the switches with a variable display that shows the specific function controlled by each switch.
To preserve the safety of operating a vehicle, it is important that the switches be easy to locate and that they provide at least a non-visual feedback to the user, such as a tactile sensation, indicating that the switch has been activated.
Accordingly, it would be useful to have a controller for operator-actuated functions located in the proximity of the operator, the controller being capable of controlling many vehicular functions through an assembly having a relatively small number of switches associated with a display of alterable function designators.